Patricia Chaves

The functions of retinoic acid (RA), a potent morphogen with crucial roles in embryogenesis including developmental hematopoiesis, have not been thoroughly investigated in the human setting. Using an in vitro model of human hematopoietic development, we evaluated the effects of RA signaling on the development of blood and on generated hematopoietic progenitors. Decreased RA signaling increases the generation of cells with a hematopoietic stem cell (HSC)-like phenotype, capable of differentiation into myeloid and lymphoid lineages, through two separate mechanisms: by increasing the commitment of pluripotent stem cells toward the hematopoietic lineage during the developmental process and by decreasing the differentiation of generated blood progenitors. Our results demonstrate that controlled low-level RA signaling is a requirement in human blood development, and we propose a new interpretation of RA as a regulatory factor, where appropriate control of RA signaling enables increased ge...

1. J Allergy Clin Immunol. 2011 Aug 11. [Epub ahead of print] T-cell involvement in delayed-type hypersensitivity reactions to infliximab. Torres MJ, Chaves P, Doña I, Blanca-López N, Canto G, Mayorga C, Blanca M. Allergy Service, Carlos Haya Hospital, Malaga, Spain. ...

Cationic amino acids are the precursors of biogenic amines, histamine from histidine, and putrescine, spermidine and spermine from arginine/ornithine (and methionine), as well as nitric oxide. These amines play important biological roles in inter- and intracellular signaling mechanisms related to inflammation, cell proliferation and neurotransmission. Biochemical and epidemiological relationships between arginine-derived products and histamine have been reported to play important roles in physiopathological problems. In this communication, we describe the construction of an expression macroarray containing more than 30 human probes for most of the key proteins involved in biogenic amines metabolisms, as well as other inflammation- and proliferation-related probes. The array has been validated on human mast HMC-1 cells. On this model, we have got further support for an inverse correlation between polyamine and histamine synthesis previously observed on murine basophilic models. These tools should also be helpful to understand the amine roles in many other inflammatory and neoplastic pathologies.